
Condensed milk is cow’s milk with most of the water boiled off and a lot of sugar added — a thick, very sweet concentrate.
Hard to replace, since a stand-in needs heavy sweetness and creamy body at once. Cream with sugar syrup comes closest — add the syrup half a barspoon at a time and taste. Unsweetened evaporated milk or plain syrup won’t do it.
Evaporated milk
Evaporated milk is concentrated milk without sugar, sterilised in the can; condensed milk has the sugar, and it is the sugar rather than the sterilising that keeps it. In the tin they look alike, but the sugar makes condensed milk noticeably sweeter and thicker — swap it in and a drink needs its syrup dropped entirely.
A sealed tin keeps for ages; once opened, refrigerate it and use within about a week.